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Even after two decades writing about the personal finance aspects of housing, Elizabeth Razzi finds there’s always more to talk about. Buying and selling, improving, insuring, squabbling with the homeowners association -- whatever the housing topic, let this be your virtual back fence.

WHO Urges Lower Threshold for Acting on Radon

Many of us shake our heads when we hear of non-smokers who develop lung cancer and wonder how they could have come down with such a brutal disease. But in many cases, scientists tell us, exposure to radon gas in their homes could have been the cause. According to the World Health Organization, between 3 and 14 percent of lung cancer cases can be blamed on exposure low- to medium-level levels of radon in homes.

WHO just recommended that countries set an action level for getting rid of radon that's lower than the one established by the U.S. Environmental Protection Agency nearly two decades ago. According to the EPA, if a radon test shows the level in your home to be 4 picocuries per liter or higher, you should re-test and then take action to reduce the level. But, even if a test shows a level of 2 picocuries per liter, the agency suggests people consider taking action.

WHO's new recommendation (which they stated in the European metric method, at 100 Becquerel per cubic metre) is equivalent to 2.7 picocuries per liter using the American measure, according to Tom Kelly, acting director of radiation and indoor air for the EPA. But he said the agency is not considering changing its recommended action level of 4, partly because the round number is easy for the public to remember.

In a phone interview, Kelly said, "There is no threshold level in which radon is safe. ... There's a lot of risk below 2.7; there's a lot of risk below four." The most important thing, he said, was just to get people to take the risk seriously, test their homes and then to perform the relatively simple and inexpensive fixes needed to reduce their exposure.

"Radon is a terrible thing," Kelly said. "More than 2,000 20,000 Americans every year are found to have lung cancer. Much of that is avoidable."

He estimated about 15 percent of homes in America would show high levels if they were tested.

Radon gas is produced by the decay of uranium in the soil. It has no color or odor and can enter homes through cracks in the the floor or foundation walls, or through slab openings for sump pumps and plumbing.

You can buy a do-it-yourself radon test kit at hardware stores for about $10. "These rugged little test kits still give you a very useful estimate," Kelly said. If it shows radon, you can follow up with more precise tests from professionals. "Remember, 4 is not safe," Kelly said. He also said it's best to do the test in the cooler months, when the house is closed up and humidity levels are low. Heat and humidity can affect readings, he said.

If you do find radon, often it can be lowered dramatically by sealing building openings and adding ventilation, especially in the basement.

Good post on a critical public health issue that most homeowners falsely assume they can safely ignore. In fact, based on calculations by the National Academies of Science, EPA estimates that more than 20,000 Americans (not 2,000) die each year from lung cancer caused by exposure to indoor radon gas. Setting the recommended action level at 2.7 vs. 4 is less important than persuading American homeowners to test their homes and take simple, proven steps to defend against radon gas intrusion. -- Tom Kelly, EPA

Thank you for the article. As a physician, I am dismayed by the lack of concern among my colleagues regarding radon. I heard a talk by Dr. Bill Field from the University of Iowa who served on the WHO committee at an occupational health meeting last year. He pointed out that radon is the leading environmental cause of cancer mortality in the United States and if I recall correctly, he also indicated it was the 8th leading cause of cancer deaths overall. I would urge the American Cancer Society (why are they not doing more?) and other public health groups to take more of an interest in the large number of radon caused deaths each year in the United States. I would also hope that the EPA would consider reducing its action level since most of the radon caused deaths are occurring BELOW the 4 picocuries per liter. The EPA’s current action level which is above the WHO recommended level now gives people the FALSE impression they are safe if they have 4.1 picocuries per liter.

While sealing the basement is an essential first step in reducing radon, it is not enough by itself, and ventilation is uncertain and often impractical for the purpose, particularly in winter. The recommended method for reducing radon in homes is called "sub-slab depressurization." After sealing the basement, a radon professional inserts a low-pressure collection pipe beneath the slab or crawlspace to gather radon gas from the soil before it enters the home. The pipe leads up through the home and releases the gas safely above the roof line. A professional radon mitigator can typically reduce radon readings well below 2 picoCuries per liter at a cost most homeowners can afford (varies by home design and placement, but typically between $1500 and $2500).